Graining process



Oct. 25, 1932. 1 v. cAsTo 1,884,566

GRAINING PROCESS Filed April 16, 1950 Gffou/voCo/ar BASE Patented Oct. 25, 1932 UNITED s-Tass PATENT OFFICE LLOYD V. GASTO, OF DETROIT, MICHIGAIYI', ASSIGNOR TO OXFORD VARNISH CORPORA- TION, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN GRAINING PROCESS Application filed April 16,

This application is a continuation in part of my prior application Serial No. 333,048, filed January 17, 1929. In my prior application, various modifications of a method or process have been described by Which natural Wood designs may be copied on materials, such as sheet metal, Wall board and the like, the method resulting in a considerably more faithful portrayal of the illusivc`color and tonal appearances of such natural Woods than can be obtained by previously known commercially practicable methods.

The prior application shows the general principles of the method, and the invention is claimed broadly. Theprior application contains specific claims to the method as pracparticularly those of the finer kinds,

ticed With a synthetic or artificially prepared designl element for producing one of the printing members, Whereas the specific claims of the present application are confined to other novel methodsof producing the cor# responding printing member.

In connection with a large-number of Wood samples, there are more than tWo c olors apparent, and the ordinary processes, which depend upon. a ground and a grain color for reproduction of the originals have been inadequate because, notwithstanding studied.

refinements of the known processes, the actual color effects or an even close simulation thereof by shading and blending two colors could not be, or at least were not, accurately reproduced.

In a'great number of varieties of Wood,

if a definite zone of a given sample is viewed at one angle, it has one color appearance and when viewed at another angle -ithas another color appearance. This is partly due to peculiar light refractions in the Wood cells, and resulting color combinations, and partly to the presence of diiferent pigmentations in the different parts. Prior to my invention, it has been practically impossible to reproduce this peculiarity occurring in various kinds of wood. f

An object of the invention is to provide a practical method of very closely simulating the \design and color effects of high grade from hand copying, as ,by an extremely 1930. Serial No. 444,882.

Wood samples on materials, such as metal, Wood, Wall board and the like.

If a sample of ordinary straight grain Walnut, finished in the usual Way, with filler and stain and protective varnish or enamel, is studied closely, there will be found a prevailing ground color, a dense or dark grain color of characteristic shades and tones, but in addition thereto an intermediate color, which is not merely a variation in shade of the ground or the grain color, but which is entirely distinct from these colors. In Walnut, for example, it may be gray or red; sometimes even green, but it is neither any combination of the ground and grain coloring nor any shade of either. For convenience, I shall refer to this as an undertone or undertone color.

A further object is to provide A,a commercially practicable process which will substantially reproduce all the colors and tonal effects of natural Woods, including the undertones, in a natural manner. By commercially practicable I'mea'n to distinguish skilled artist, whereby practically anything 75 may, of course, be copied. Y

At this point, it may be stated that, in general, any of the various known grain reproduction methods may be used in applying the pigment materials necessary to effect reproductions, in connection With the essential improvements demonstrated in this application. For example, a practical and Very effective method is disclosed in the patent to J. P. Henry, N o. 1,548,465, issued August 4, 1925. This process consists in etching a suitable roll or plate using a carbon tissue exposed through a photographic film or plate bearing the light and dark contrast and tonal effects of the grain to be copied. The resist is used in etching the plate or roll and the result is a printing member to Which mayv be applied a suitable pigment film, the plate or roll being afterwards scraped of excess pigment, leaving a pigment design in the etched pockets Which is then suitably transferred to the work to be grained.

A process similar to the above, in so far as the present method is concerned, is the so- 1W etV called half-tone process. There are many variations of this. For further example, there is the process of etching out, or otherwise removing, the softer parts of a piece of wood in flat or cylindrical form and using this as a printing member for direct or ofiset printing, which member may of course be made to constitute either an intaglio or a relief printing member, as desired. Other processes include forming the pattern in relief, or for that matter intaglio, on a resilient roll, such as the ordinary gum transfer roll and printing direct on the work with such roll. There are several known methods of producing such a gum roll with grain effects thereon. The planographic processes m1-y, of course, also be used, as in lithograp gescription of a number of contemplated variations or modifications of my method are given below. The broad idea of the various modifications of the process is illustrated in the drawing in which Fig. 1 is a cross-section showing the base with a ground coat applied thereto; Fig. 2 is a similar cross-section showing the base with the ground coat and the tomng transfer applied thereto, and Fig. 3 is a cross-section of the base having the ground coat toning transfer and graining transfer applied thereto. The drawing is intended only to illustrate the general features of the process, the various methods of carrying out the process being described in detail below. Suitable le nds have been applied to the drawing to lecilitate an understanding of the invention, but it is to be understood that such legends in no way limit the scope of the invention as defined in the appended claims.

Modification N o. 1

Starting with a suitable anel or like piece of work to be grained, the base), this is first treated to produce thereon a ground color appearance, the color substantially corresponding to the predominating ground color of the wood to be copied, but the shade of which may be varied from the original, as will be hereinafter discussed. In case the base is naturally of the desired ground color, no special preparation is, of course, necessary. I then transfer to the panel, a design layer of pigment havin a color or shade substantially correspon ing to the intermediate color on the original sample, that is, a color or shade intermediate the full grain lines and the ground. In effecting such transfer, it is understood that any of the printing methods, such as above discussed, may be used. For example, in this and all the modifications hereinafter described, suppose the pattern element is an etched intaglio roll and the transfer is effected by means of a resilient roll which takes up the pigment from the interstioes of the intaglio plate or roll and transfers it to the panel on top of the ground color. This first imprint is in a color range darker than the ground, but lighter than the darkest portion of the original subject. In this particular modification, the first imprint transfers the design of the subject representing the grain in substantially all of its tones.

The second (grain transfer) impression is now made from the sameprintingelement that was used for the first impression (undertone transfer), either in or out of registration with the first impression. If made in true registration, considerable of the intermediate or undertone color will be seen, notwithstanding that the second impression overlies this. lThis is mainly due to the fact that the two imprints cannot, as a matter `of practice, be made absolutely accurately and color will be missin from both. It follows that where the second impression is not complete, the color transferred by the first impression will be in full view. Where not in full view, it will be seen through the color transferred by the second impression, sincein any event the pigment materials used are transparent to a greater or less degree, depending, in the intaglio process for example, on the depth of the color retaining pockets. The second impression is made with a color which either by itself or in combination with the first impression color and the ground color, effects the desired full grain color in all of its tones, but it is practically essential that the actual color used for the second impression be of a shade darker than the ground and the intermediate color as well.

Modiaaeon No. e

In this modification, two different pattern transferring elements are used to make impressions on top of the ground color, which latter is determined by the wood to be copied.

The first design impression is made from an element prepared artificially, an example being where a. transparent or translucent sheet of material receives a design, made as by an air brush, which corresponds to the areas on the original subject where the intermediate color is apparent. Such transparent sheet is used in the manner of a positive photographic print to make an etch resist in the ordinary wa (see the Henry patent, for example).

nstead of making the design on a transparent or translucent medium, I` may make the design on opaque material and photograph the design, arriving at substantially the same result as will be obvious.

The intermediate color used in this modification is comparatively light, that is to say, it is not much darker (farther down the color shade range) than the ground color. This is placed on the work as in the first modification. The second impression is made from a pattern element repared to bring out the darkest tones of t e grain design, and a dark Modiycatz'on No. 3

This, of course, includes the usual ground color step as before.

The design printing element for the first impression is prepared mainly for tone, and

the sharp grain design is very subdued. I may prepare an intaglio plate or roll for example, by etching the tone portions, and the grain portions of nearly uniform depth by using a comparatively strong acid and etching rapidly, whereby the acid'will penetrate the resist in the blacks and middle tones thereof, almost at the same time, resulting in a. plate in which the distinctive grain pattern is almost lost. .Y

.The second plate or roll is prepared to transfer the sharp grainy lines in at least. part of the tones. For this, the sharp contrasts may be brought out in the etching process. For example, the etching may be performed using a heavy gravity acid and etching slowly. In doing this, the etching process is stopped before the heavy layers of the geltine of the resist are penetrated by the aci J l In this modification No. 3, the second impression plate or roll is deeply etched and a darker color is used than in the first impression.

Modification N o. 4

fter the ground color step, the first design is made from a plate orlroll prepared mainly for tone and is varied according to the wood to oe reproduced. The expedient above -deseriiied, with reference to Modification No. 3,

for eliminating sharp grain contrasteffects may be used. A light color pigment is used with the first plate or roll. i

In this modification, the second design 1mpression is made from a plate or roll prepared mainly to bring out the grain in sharply contrasting effect, as previously described, but with very little or no tone. The plate or roll .is deeply etched and a dark color is used.

In order to etch the plate or roll deeply while still eliminating all the `tones of the grain design, a so-called contrasty photographic reproduction is used in preparing the resist.

Modiicatz'on N o. 5

in sharp contrast (no tonal effects). The

plate or roll is deeply etched and a dark coloil Modication N o. 6

After the ground color step, an impression is made from a plate or roll preparedfor both tone and grain, but with a shallow etching, and a light color is used.

The second impression is made with a plate or roll prepared for both tone and grain and deeply etched. A dark color is used as in Modifications 3 to 5.

Modiycatz'on N o. 7

In this modification, the first design impression is made over the ground color with a plate or roll prepared for both tone and grain. The plate or roll is deeply etched and a light color is used.

The second design impression is made from a plate or roll etched for grain only, either deeply etched or shallow, as called for by the wood to be copied. In case of a shallovi etch, a darker color is usually used than would be required for a deep etch.4

It will be observed from the above that both the impressions may be in the same color, if one plate or roll is etched for tone particularly and the other plate or roll is etched to bring out particularly the grain in sharp contrast. This will not truly copy the additional color effects (undertones) peculiar to some types of Wood samples but it will produce a more faithful representation of such woods than can be obtained by previously known methods using one grain imprint.

It will be seen from the above that the general underlying idea of the process is to use a combination of equipment in which one element of the equipment stresses particularly what the other lacks. For example, if the plate or roll used to make the first impression is etched or prepared for tone, the second plate or roll will be etched or prepared prikis used.

`marily for grain or sharp contrasts. It is important in all the above specifically discussed modications of the method, to confine each of the two impressions to a color shade differing from the other, and both must be darker than the ground color.

In carrying out the above method in any of the illustrative modifications, it is to be borne in mind that great improvements are noted over the old methods of single impression graining, that is, one grained pattern impression with a suitable pigment, transferred over a plain ground color, whether or not the two impressions are in true registration, or definitely out of registration. Because of this, in certain woods a master toning plate or roll may be used, for a number of actually different patterns, the definite characteristic grain effects of which will be brought out by the dark-colored plate or roll, thus eecting a great saving in equipment cost. This variation is particularly useful in reproducing straight grained walnut and mahogany for example, but it is not, so far, been found entirely satisfactory in connection with butt and burl samples. In general, it is immaterial whether such master plate or roll is produced using a synthetic pattern made as by hand tracing on a transparent sheet of material, as above described, or whether made photographically from an actual wood sample or of a suitable design.

A distinction, from known multi-color methods, is that the two impressions may be definitely out of register and no special care need be exercised as to this. Satisfactory work is produced notwithstanding non-registration. It is, in general, true that no quantity production graining method on materials other than fiat panels, can be successful where absolute registration of two color impressions must be maintained.

Modification N 0. 8

In carrying out the present method, a combination of approximate registration together with definite non-registration is sometimes used. An example is where two plates or rolls are used to reproduce matched grain e'ects, as Where two or more abutting similar veneer sections form the original subject. Suppose the original subject is a two-way or four-way match, butt walnut sample.

`Here it will be apparent that if the two design impressions are not approximately in register at the joint line, a double joint line effect will appear which will, of course, detract materially from the appearance of the work produced. Consequently, for this particular work, approximate registration must be had as to the oint line. It sometimes follows that the grain lines of both impressions will almost but not exactly register. In such and similar cases, the use of the two impressions sometimes results in what has been termed adizzy effect. An illustration of this effect is where a photostatic print is made in which the subject or the camera is moved very slightly during the exposure. The resulting picture appears to be moving and cannot be viewed without straining the eye. To prevent this dizzy effect, I use a device which consists in slightly enlarging or reducing one of the photographic reproductions in the chain of steps necessary to produce, say a carbon resist for one of the plates. For the other plate, no enlargement or reduction is made. The result is that the two patterns are not in the same scale and no absolute registration of one imprint with the other is possible. In this case, of course, the dark color plate or roll would be made t0 transfer' a clear and sharp impression of the gram.

It Will be understood from the above that 5 while it is not entirely essential that the toning plate or roll be impressed first on the work and the plate carrying the darker color effects produced second, it has been noted that the work is much superior in quality where the light color impression is made first and the dark color impression second.

Obviously, the process may be modified to f the extent of using any number of transfer impressions for a single subject, that is, instead of simply using two transfers, in addltion to the ground, three and possibly more may be used.

I claim:

1. The method 'of reproducing natural grain subjects on a suitable base, comprising, treating the base to cause it to represent substantially the ground color of the selected subject, preparing a printing member by taking a photograph of the Aselected subject and transferring the grain design therefrom to the member by a photo-engraving process including using a fast acting mordant during the etching of the member to cause the member to carry the grain design in sharp contrast, similarly preparing another printing member but varying the preparation by using a slow acting mordant to cause the member to carry the grain greatly subdued, that is non-contracting, and making successive pigment imprints of the two members on the base.

Q. The method of reproducing natural grain subjects comprising, preparing a printing member by making a photographic reproduction of the grain design of the selected subject and transferring the grain design therefrom to the member through a series of substantially conventional photo-engraving steps but characterized in that the etching step is controlled to cause the member to carry the grain design in sharp contrast, similari)7 preparing another printing member through a photographic reproduction but controlling the etching step to cause the member to carry the grain greatly subdued, and making successive imprints of the two members on a Ybase representing the ground color of the grain subject.

3. The method of reproducing natural grain subjects on suitable bases, comprisin treating the base to cause it to have a groun color appearance, preparing a plate or roll photographically and by deep etching with a quick acting mordant whereby the design of the subject thereon emphasizes the tone qualities of the original subject and the plate will hold a super-quantity of pigment material, preparing another vplate or roll photographically and by etching with a slow acting mordant whereby only the grain of the original subject is represented, and causing successive impressions from each plate or roll to be made on the base.

4. The method of reproducing wood grain effects on suitable bases, comprising, treating the base to cause it to represent substantially the ground color of the selected subject, preparing a plate or roll photographically and by etchiiig, using a heavy gravity acid and etching slowly to subdue the grain contrast, preparing another plate or roll photographically and by etching, using a low gravity acid and etching rapidly to bring out the grain design in sharp contract, applying pigment to the two plates or rolls and separately imprinting the design thereof onto the base over the ground color.

5. The method of reproducing natural grain subjects comprising, treating a suitable base to represent substantially the ground color of they selected subject, preparing a. slightly etched master toning printing member having an indefinite design thereon rela.- tive to the natural grain to be simulated, making a pigment impression from such member on the base by the use of a transfer roll, preparing another printing member through a photographic reproduction of the actual grain design of the specic selected subject to be reproduced and printing therefrom onto the base by the use of a transfer roll.

In testimony whereof, I hereunto aiix my signature.

LLOYD V. GASTO. 

